When processing the work, using a device, for an engine and an impeller, which has many narrow portions and curved surfaces, it is necessary to appropriately design a processing path of the tool so as to prevent the device and the tool from interfering with the work. Recently, CAM technique has been employed for designing the processing path by modeling the device, the tool and the work preliminarily in the computer as three-dimensional models using computer simulation technique before processing, and changing a position and posture of the tool model with respect to the computer models of the device and the work along the processing path so as to calculate as needed whether the interference occurs between the models.
For example, FIG. 1 illustrates that an impeller 102 as the work is subjected to cutting work by a 5-axis CNC machining device 101. In this state, a tool 103 is required to cut the curved surface while getting into a narrow portion of the impeller 102 where blades are overlapped. It is therefore necessary to generate the path of the tool 103 so as to protect the impeller 102 from interference of the portion of the tool 103 other than a blade edge and the device 101. In this processing path generation, the processing path is generated on the CAM device, and thereafter, an operator checks whether there is the interference on the processing path in reference to computer graphics of the CAM device. If the interference is found, the operator corrects posture and path of the tool based on experience and intuition, and resumes the interference check repeatedly.
Following cases will be described as related art. Patent Literature 1 proposes the method for improvement of display with respect to interference on the processing path of the CAM device. Specifically, the part of the tool is classified into the one for processing in contact with the work, for example, a blade edge, and the one not for processing. If the interference with the work occurs at the part of the tool, which is not used for the processing, the display color of the CAM device will be changed to allow easy identification of the interference state. The display color of a trajectory of the tool on the work is made different from that of the work so as to further allow easy identification of the specific point on the processing path where the interference has occurred.
Patent Literature 2 proposes the method for high speed interference check in the CAM device. Specifically, the device, tool and work are converted into graphic data, respectively by the CAM device. Unlike the interference check operation performed by image processing for the respective graphic data to determine whether there is an overlap of the processed graphic data, the interference check is performed through logical operation after converting the graphic data into serial signals, thus establishing high speed operation.
Non-patent Literature 1 proposes the method for improvement of display of the part of the industrial tool on the processing path where the interference occurs in the CAM device. Specifically, the processable region and the non-processable region are graphically illustrated in configuration space of the tool, which is defined by the tool feed direction and the normal direction at a point in contact with the work. The direction of the tool where the interference with the work occurs in the non-processable region is color displayed so as to ensure easy identification of the interference state.
For the color display of the interference direction, when the processing surface of the work is geometrically expanded to the center of the tool, the expanded surface that interrupts the line of sight radially extending from the center of the tool is regarded as the interference. The color imparted to the line of sight is mapped in the tool configuration space as the color representative of the interference state so as to allow determination with respect to direction of the tool in which the interference with the work occurs in the non-processable region based on the color.
Non-patent Literature 2 proposes the method of generating the processing path in the CAM device, which avoids the interference in accordance with the operator's instruction as needed. Specifically, the mechanism is provided to allow the operator to operate a multilinked manipulator added to the CAM device so as to adjust posture and position of the tool in the CAM device. A force sensor is added to the manipulator, which executes a force feedback to limit the work range of the manipulator so that the tool is no longer advanced toward the interfering direction where the tool has interfered with the device and the work in the CAM device, and the operator is notified of the interference state. The color of the region of the work surface in the CAM device, which is processed by the manipulation is changed to a different color to assist generation of the processing path.